Compromise

Pierre,

Could you give a for instance, or two, so that my artist's brain can switch over to my science brain and run with that? ;-)

 

Good eye and common sense.
One is the science of the oculars, the other is the art of compromise.
Both connect usually to accomplish the function asked to make

 

Gosh, Ive just read the posts following my last one and I'm open mouth. Rick, do you call that requirements? Fetch of 5 km in a sheltered lake? that must give frightening waves...5m deep mooring, I was afraid it was the Baikal, 1650m deep if I'm not mistaken and so on. It's ridiculous.

Let's start with true requirements on a true boat:
1- Tight budget. More than tight. That has a lot of consequences, some very good.
2- Mission: public service patrol boat. Protection and surveillance of fisheries in the 200 nm of the economic zone. Rescue, fire fighting, pollution fighting and maritime police in Atlantic, Iroise Sea, Irish Sea, Channel, North Sea, North Atlantic. in third the natural consequence:
3- All weather capable.
4- Derivation from 1-; LOA max 55m, max weight 500 metric tons.
5- Speed 22 knots.
6- Able to cross the Atlantic at economical speed.
7- Derivation of 2-, able to maintain mini 15 kn in sea state 7 against the wind, full weight.
8- Crew max 25 persons including medical crew. Possibility to take 30 other persons for a short time for example after a rescue.
9- Built DNV rules.
I won't detail all the requirements. The SOR book is rather thick...
Answer after hundred of design compromises, or choices, the nice word preferred by Mr Tanton:
Dimensions
LOA :54 m
Displacement light : 300 metric t
Displacement max : 477 metric t
Propulsion
2 diesel engines Deutz-MWM TBD 620 V 16 de 3 050 ch
2 diesel engines Deutz-MWM TBD234 V 12 de 930 ch. 2 propellers variable pitch.
Electric power : 380 kW
Distance 4500 nm at 14 kns.
Max speed : 23 kns (43 km/h)
Water canon 400 m3 (105,680 gallons) hour at 10kg/cm2 (140 PSI).
Crew 21 plus medics.
Construction cheap and simple in steel, V hull.
A few pics follow.

I could say the same of a high sea tug, a high sea fishing boat, a freighter, a fast ferry, a record breaker multihull, and many other big or small, but please

 

I prefer the word torture

Ive been working on a design for almost a year now and its an endless compromise

length constrained by cost as is beam
power to the cost of sail or fuel
finish is depending on how much time I have to throw at it
material a mater of weight and cost
size of various rooms and walks is all about compromise
everything is in some way or another a compromise the sum total of which is
torture

B

 

Pics Net Marine, Copyright owners marked on pics. Pics used for illustration purposes.
The third pic is the little surprise: rear door for the fast intervention boat used for police and rescue.

 

It was not intended to be specific in any way. It was simply to point out that there is no need to compromise on requirements where there is large design space. This disproves the proposition the "All things in yacht design are a compromise".

I have given an example where no requirements have to be comprised.

Rick

 

I just noticed someone voted no
any idea who that might have been?

 

Those who are trying to optimise propellers for their boats using the best propeller software often go through two or more alterations on propellers before they get something that they consider acceptably close in the real world to what was predicted by the computer. The difference is the assumptions made in the program vs the real world on the end of a propeller shaft.

 

Rick by your requirements I would design a rectangular raft made of standard lumber and 55 gallon drums with a Z drive. I doubt it would be what you had in mind. The compromises from your brain to what would be in front of you would likely involve to much compromise for your liking.

 

The query was about the computer programs, to which you refer in the subject of the first quote. Apologies for not making that more clear.

I have a solid understanding of the creative process as it can be aided by the design software available.

What I would like to know... can you give me an example, or two, of the many software compromises which prevent optimization. I use Rhino3D and Orca on a regular basis and ProE every once in awhile, if that helps.

 

And I expect that is something you would be proud of.

Rick W

 

To make it possible to have a perfectly optimized boat there's awfull lot of compromises done while writing the SOR's

 

Only if your funds are limited.

Rick W

 

Rick... You seem hell bent on making your position more absurd with every post. In the interests of world peace, let me try to put an end to this...

Rather than your current no compromise position, would be happy to agree that:
Compromise is an unfortunate but necessary component of yacht design, but one should always strive for the optimum outcome.

??

 

I was very happy with what MikeJohns posted From the author of his reference text it shows great insight given the publication date. That aligns well with my view.

The word compromise does not come into it.

Rick W